Hi! I'm a registered nurse so I was gonna ask a couple more questions. You said you had blood work done but exactly what kind of blood work. There are many things that physiologically can cause hair thinning such as anemia, thyroid disease, autoimmune diseases, androgenetic alopecia, polycystic ovary syndrome, and skin conditions. I would recommend seeing a dermatologist about this, maybe one who specializes in hair and scalp conditions. Since you mention the hair loss is along your hairline, there is such a thing as traction alopecia caused from placing too much tension on your hairline with ponytails, braiding, etc.

I think as long as you are using a color rinse on your hair that doesn't contain peroxide or ammonia you should be fine. I only use semi-permanent color on my hair by Loreal Healthy Look or Clairol Natural Instincts. This color won't lighten hair at all but just coats the hair shaft and rinses out over a number of washes.

You should also be doing weekly deep conditioning. There are several out there that are great and don't have to be expensive either.

Keep in mind that the Curly Girl method doesn't work for everyone. It didn't work for me and my hair at all. My hair does fine whether I use sulfate shampoo or not.